nuclear@0: #include "box.h"
nuclear@0: 
nuclear@0: Box::Box()
nuclear@0: 	: min(-0.5, -0.5, -0.5), max(0.5, 0.5, 0.5)
nuclear@0: {
nuclear@0: }
nuclear@0: 
nuclear@0: Box::Box(const Vector3 &min_arg, const Vector3 &max_arg)
nuclear@0: 	: min(min_arg), max(max_arg)
nuclear@0: {
nuclear@0: }
nuclear@0: 
nuclear@0: bool Box::intersect(const Ray &inray, HitPoint *pt) const
nuclear@0: {
nuclear@0: 	Ray ray = inray.transformed(inv_xform);
nuclear@0: 
nuclear@0: 	Vector3 param[2] = {min, max};
nuclear@0: 	Vector3 inv_dir(1.0 / ray.dir.x, 1.0 / ray.dir.y, 1.0 / ray.dir.z);
nuclear@0: 	int sign[3] = {inv_dir.x < 0, inv_dir.y < 0, inv_dir.z < 0};
nuclear@0: 
nuclear@0: 	float tmin = (param[sign[0]].x - ray.origin.x) * inv_dir.x;
nuclear@0: 	float tmax = (param[1 - sign[0]].x - ray.origin.x) * inv_dir.x;
nuclear@0: 	float tymin = (param[sign[1]].y - ray.origin.y) * inv_dir.y;
nuclear@0: 	float tymax = (param[1 - sign[1]].y - ray.origin.y) * inv_dir.y;
nuclear@0: 
nuclear@0: 	pt->normal = Vector3(ray.origin.x > 0.0 ? 1 : -1, 0, 0);
nuclear@0: 
nuclear@0: 	if(tmin > tymax || tymin > tmax) {
nuclear@0: 		return false;
nuclear@0: 	}
nuclear@0: 	if(tymin > tmin) {
nuclear@0: 		pt->normal = Vector3(0, ray.origin.y > 0.0 ? 1 : -1, 0);
nuclear@0: 		tmin = tymin;
nuclear@0: 	}
nuclear@0: 	if(tymax < tmax) {
nuclear@0: 		tmax = tymax;
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	float tzmin = (param[sign[2]].z - ray.origin.z) * inv_dir.z;
nuclear@0: 	float tzmax = (param[1 - sign[2]].z - ray.origin.z) * inv_dir.z;
nuclear@0: 
nuclear@0: 	if(tmin > tzmax || tzmin > tmax) {
nuclear@0: 		return false;
nuclear@0: 	}
nuclear@0: 	if(tzmin > tmin) {
nuclear@0: 		pt->normal = Vector3(0, 0, ray.origin.z > 0.0 ? 1 : -1);
nuclear@0: 		tmin = tzmin;
nuclear@0: 	}
nuclear@0: 	if(tzmax < tmax) {
nuclear@0: 		tmax = tzmax;
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	float t = tmin < 1e-4 ? tmax : tmin;
nuclear@0: 	if(t >= 1e-4) {
nuclear@0: 		pt->obj = this;
nuclear@0: 		pt->dist = t;
nuclear@0: 		pt->pos = ray.origin + ray.dir * t;
nuclear@0: 		pt->pos.transform(xform);
nuclear@0: 		pt->normal.transform(dir_xform);
nuclear@0: 		return true;
nuclear@0: 	}
nuclear@0: 	return false;
nuclear@0: }